A Critical Overview of Current Theoretical Methods of Estimating the Energy of Intramolecular Interactions.

Mirosław Jabłoński

doi:10.3390/molecules25235512

Abstract

This article is probably the first such comprehensive review of theoretical methods for estimating the energy of intramolecular hydrogen bonds or other interactions that are frequently the subject of scientific research. Rather than on a plethora of numerical data, the main focus is on discussing the theoretical rationale of each method. Additionally, attention is paid to the fact that it is very often possible to use several variants of a particular method. Both of the methods themselves and their variants often give wide ranges of the obtained estimates. Attention is drawn to the fact that the applicability of a particular method may be significantly limited by various factors that disturb the reliability of the estimation, such as considerable structural changes or new important interactions in the reference system.

Highlights

Intermolecular hydrogen bonds [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16] occupy the main place among various intermolecular interactions
Waals interactions [7,11] and much stronger chemical bonds [1,17]. It is this intermediate strength of intermolecular hydrogen bonds that allows for them to act as a glue that binds various molecules into dimers or larger molecular aggregates
C=C double bond obviously leaves the H atom rotated with this group on the “inside” of the molecule, i.e., at the R3 site and close to R1 .) Because EZ and EE conformers are used in Rotamers Method (RRM) and Geometry-Corrected Method (GCM), it is obvious that the results that are presented by Nowroozi and Masumian [63] are completely wrong

Summary

Introduction

Intermolecular hydrogen bonds [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16] occupy the main place among various intermolecular interactions. One of the possible ways of assessing the reliability of the obtained energy value is comparing it to the appropriate intermolecular interaction, in which the type of X and Y atoms (from the XH· · · Y contact), and their spatial configuration (e.g., the key distance H· · · Y) is largely preserved. Another sensible possibility is to check the fulfillment of various correlations between the found energy values and other parameters describing the strength of the H· · · Y bond. I will limit myself to a few examples that illustrate how a given method works

Conformational Methods

QTAIM-Based Methods

Empirically-Based Methods

Iogansen’s Relationship

Chemical Shift—Based Method

Summary